I had my GSA in for service last week. As a loaner I was given a R1200rs.
Although the RS was not for me, I was shocked at how much better the quick shifter was on this bike.
The feel of it and the gear lever was like chalk and cheese compared to my GSA.
I was guessing that the RS has a very different gear box as it felt quite different in 1st as well ie when in 1st if you press the lever down - on the GSA it feel rock solid (bottom of the box) on the RS it was like there was a rubber stopper that in 1st if you pressed down was up against.
Would be interested to know if anyone knows the differences in gearbox between a GSA no a RS as like I said they felt completely different when paired with GSAP.